I don’t have access to any modern day diagnostic tools, so I’m using what they had in 1946.
I backed off the advance a few degrees and no difference.
Bearing in mind that even when it was running at the recommended settings of 5 degrees BTDC it was no different.
Pulling the choke out when it starts pinging makes no difference at all.
I’ve tried one of those combustion chamber cleaners a bit like your Seafoam, and it’s better. Not perfect but better.
The only way to stop it pinging completely is to back off the throttle.
In a modern car I’d just change gears, but with this 3 speed box changing down to 2nd above about 10mph is not an option.
Until I can take the head off and clean the combustion chambers and valves I might just have to live with it.
